Planarizing machines and control systems for mechanical and/or chemical-mechanical planarization of micro electronic substrates

Abstract

A system for controlling a mechanical or chemical-mechanical planarizing machine comprises a light system, a sensor, and a computer. The light system can have at least a first emitter that generates a first light pulse having a first color and a second emitter that generates a second light pulse having a second color different than the first color. The first and second light pulses reflect from a microelectronic substrate in a manner that creates a first return light pulse corresponding to a reflectance of the first light pulse and a second return light pulse corresponding to a reflectance of the second light pulse. The sensor receives the first return light pulse and the second return light pulse, and the sensor generates a first measured intensity of the first return light pulse and a second measured intensity of the second return light pulse. The computer has a database and a computer readable medium. The database contains a plurality of sets of reference reflectances in which each set has a first reference component defined by a reflectance intensity of the first light pulse and a second reference component defined by a reflectance intensity of the second light pulse from a selected surface level in a layer of material on the microelectronic substrate. The computer readable medium contain a computer readable program that causes the computer to control a parameter of the planarizing machine when the first and second measured intensities correspond to the first and second reference components of a selected reference reflectance set.

What is claimed is:  
     
       1. A system for controlling a mechanical or chemical-mechanical planarizing machine that planarizes microelectronic substrates, comprising: 
       a light system having a light source comprising at least a first emitter that generates a first light pulse having a first color and a second emitter that generates a second light pulse having a second color different than the first color, wherein the light source is configured to direct the first and second light pulses toward a front surface of a microelectronic substrate in a manner that creates a first return light pulse corresponding to a reflectance of the first light pulse and a second return light pulse corresponding to a reflectance of the second light pulse;  
       a sensor configured to receive the first return light pulse and the second return light pulse, the sensor being capable of generating a first measured intensity of the first return light pulse and a second measured intensity of the second return light pulse; and  
       a computer coupled to the sensor, the computer having a database and a computer readable medium, the database containing a plurality of sets of reference reflectances in which each set has a first reference component defined by a reflectance intensity of the first light pulse and a second reference component defined by a reflectance intensity of the second light pulse from a selected surface level in a layer of material on the microelectronic substrate, and the computer readable medium containing a computer readable program that causes the computer to control a parameter of the planarizing machine when the first and second measured intensities correspond to the first and second reference components of a selected reference reflectance set.  
     
     
       2. The system of  claim 1  wherein: 
       the database includes an endpoint reference reflectance set having a first reference component corresponding to a first endpoint intensity of the first return light pulse from an endpoint surface and a second reference component corresponding to a second endpoint intensity of the second return light pulse from the endpoint surface; and  
       the computer readable program causes the computer to terminate a planarizing cycle when the first and second measured intensities correspond to the first and second endpoint intensities, respectively.  
     
     
       3. The system of  claim 1  wherein: 
       the first emitter comprises a red LED that generates a red first light pulse having a wavelength of approximately 600 nm to 780 nm; and  
       the second emitter comprises a green LED that generates a green second light pulse having a wavelength of approximately 490 nm to 577 nm.  
     
     
       4. The system of  claim 1  wherein the sensor includes a single photo detector that measures both the first intensity of the first return light pulse and the second intensity of the second return light pulse. 
     
     
       5. The system of  claim 1  wherein the light source further comprises a third emitter that generates a third light pulse having a third color different than the first and second colors. 
     
     
       6. The system of  claim 5  wherein: 
       the first emitter comprises a red LED that generates a red first light pulse having a wavelength of approximately 600 nm to 780 nm and a red first return light pulse;  
       the second emitter comprises a green LED that generates a green second light pulse having a wavelength of approximately 490 nm to 577 nm and a green second return light pulse; and  
       the third emitter comprises a blue LED that generates a blue third light pulse having a wavelength of approximately 450 nm to 490 nm and a blue third return light pulse.  
     
     
       7. The system of  claim 6  wherein: 
       the database includes an endpoint reference reflectance set having a first reference component corresponding to a first endpoint intensity of the red first return light pulse from an endpoint surface, a second endpoint component corresponding to a second endpoint intensity of the green second return light pulse from the endpoint surface, and a third reference component corresponding to a third endpoint intensity of the blue third return light pulse from the endpoint surface; and  
       the computer readable program causes the computer to terminate a planarizing cycle when the first, second and third measured intensities correspond to the first, second and third endpoint intensities, respectively.  
     
     
       8. The system of  claim 6  wherein: 
       the database includes a reference reflectance set corresponding to an interface between two layers of material on a substrate, wherein the reference set has a first reference component corresponding to a first interface intensity of the red first return light pulse from an interface surface, a second reference component corresponding to a second interface intensity of the green second return light pulse from the interface surface, and a third reference component corresponding to a third interface intensity of the blue third return light pulse from the interface surface; and  
       the computer readable program causes the computer to indicate when the first, second and third measured intensities correspond to the first, second and third interface intensities, respectively.  
     
     
       9. A system for controlling a mechanical or chemical-mechanical planarizing machine that planarizes microelectronic substrates, comprising: 
       a light system having a light source comprising at least a first emitter that generates a first light pulse having a first color and a second emitter that generates a second light pulse having a second color different than the first color, wherein the light source is configured to direct the first and second light pulses toward a front surface of a microelectronic substrate in a manner that creates a first return light pulse corresponding to a reflectance of the first light pulse and a second return light pulse corresponding to a reflectance of the second light pulse;  
       a sensor configured to receive the first return light pulse and the second return light pulse, the sensor being capable of generating a first measured intensity of the first return light pulse and a second measured intensity of the second return light pulse;  
       a computer coupled to the sensor, the computer having a database and a computer readable medium, the database containing a plurality of sets of reference reflectances in which each set has a first reference component defined by a reflectance intensity of the first light pulse and a second reference component defined by a reflectance intensity of the second light pulse from a selected surface level in a layer of material on the microelectronic substrate, and the computer readable medium containing a computer readable program that causes the computer to control a parameter of the planarizing machine when the first and second measured intensities correspond to the first and second reference components of a selected reference reflectance set wherein the light source further comprises a third emitter that generates a third light pulse having a third color different than the first and second colors;  
       the first emitter comprises a red LED that generates a red first light pulse having a wavelength of approximately 600 nm to 780 nm and a red first return light pulse;  
       the second emitter comprises a green LED that generates a green second light pulse having a wavelength of approximately 490 nm to 577 nm and a green second return light pulse; and  
       the third emitter comprises a blue LED that generates a blue third light pulse having a wavelength of approximately 450 nm to 490 nm and a blue third return light pulse; and  
       wherein the sensor comprises a single photo detector that measures the first intensity of the red first return light pulse, the second intensity of the green second return light pulse, and a third intensity of the blue third return light pulse.  
     
     
       10. A system for endpointing a mechanical or chemical-mechanical planarizing machine that planarizes microelectronic substrates, comprising: 
       a light source having a first emitter that emits a first light pulse having a first color and a second emitter that emits a second light pulse having a second color different than the first color, the light source being configured to direct the first light pulse and the second light pulse against a front surface of a microelectronic substrate to create a first return light pulse from the first light pulse and a second return light pulse from the second light pulse;  
       a light sensor having a single photo detector configured to receive the first return light pulse and the second return light pulse, wherein the photo detector measures a first intensity of the first return light pulse and a second intensity of the second return light pulse; and  
       a controller coupled to the light sensor, the controller changing a parameter of a planarizing cycle for the microelectronic substrate when the first and second intensities of the first and second return light pulses correspond to a set of first and second reference reflectance intensities at a selected stage of the planarizing cycle.  
     
     
       11. The system of  claim 10  whereon the controller comprises a computer having: 
       a database containing the set of first and second reference reflectance intensities at the selected stage of the planarizing cycle; and  
       a computer readable program that causes the computer to change a parameter of the planarizing cycle when the first and second intensities of the first and second return light pulses correspond to the set of first and second reference reflectance intensities at the selected stage.  
     
     
       12. The system of  claim 11  wherein: 
       the database includes an endpoint reference reflectance set having a first reference component corresponding to a first endpoint intensity of the first return light pulse from an endpoint surface and a second reference component corresponding to a second endpoint intensity of the second return light pulse from the endpoint surface; and  
       the computer readable program causes the computer to terminate a planarizing cycle when the first and second measured intensities correspond to the first and second endpoint intensities, respectively.  
     
     
       13. The system of  claim 10  wherein: 
       the first emitter comprises a red LED that generates a red first light pulse having a wavelength of approximately 600 nm to 780 nm; and  
       the second emitter comprises a green LED that generates a green second light pulse having a wavelength of approximately 490 nm to 577 nm.  
     
     
       14. The system of  claim 10  wherein the light source further comprises a third emitter that generates a third light pulse having a third color different than the first and second colors. 
     
     
       15. The system of  claim 14  wherein: 
       the first emitter comprises a red LED that generates a red first light pulse having a wavelength of approximately 600 nm to 780 nm and a red first return light pulse;  
       the second emitter comprises a green LED that generates a green second light pulse having a wavelength of approximately 490 nm to 577 nm and a green second return light pulse; and  
       the third emitter comprises a blue LED that generates a blue third light pulse having a wavelength of approximately 450 nm to 490 nm and a blue third return light pulse.  
     
     
       16. The system of  claim 15  wherein the single photo detector measures the first intensity of the red first return light pulse, the second intensity of the green second return light pulse, and a third intensity of the blue third return light pulse. 
     
     
       17. The system of  claim 15  wherein: 
       the database includes an endpoint reference reflectance set having a first reference component corresponding to a first endpoint intensity of the red first return light pulse from an endpoint surface, a second endpoint component corresponding to a second endpoint intensity of the green second return light pulse from the endpoint surface, and a third reference component corresponding to a third endpoint intensity of the blue third return light pulse from the endpoint surface; and  
       the computer readable program causes the computer to terminate a planarizing cycle when the first, second and third measured intensities correspond to the first, second and third endpoint intensities, respectively.  
     
     
       18. The system of  claim 15  wherein: 
       the database includes a reference reflectance set corresponding to an interface between two layers of material on a substrate, wherein the reference set has a first reference component corresponding to a first interface intensity of the red first return light pulse from an interface surface, a second reference component corresponding to a second interface intensity of the green second return light pulse from the interface surface, and a third reference component corresponding to a third interface intensity of the blue third return light pulse from the interface surface; and  
       the computer readable program causes the computer to indicate when the first, second and third measured intensities correspond to the first, second and third interface intensities, respectively.  
     
     
       19. A planarizing machine for mechanical and/or chemical-mechanical planarization of a microelectronic substrate, comprising: 
       a table having a support surface;  
       a planarizing pad on the support surface of the table;  
       a substrate carrier assembly having a drive system and a carrier head coupled to the drive system, the carrier head being configured to hold a substrate and the drive system be capable of moving the carrier head to engage the substrate with the planarizing pad, wherein the carrier head and/or the table is movable relative to the other to rub the substrate against the planarizing pad;  
       a light system having a light source comprising a first emitter that generates a first light pulse having a first color and a second emitter that generates a second light pulse having a second color different than the first color, wherein the light source is configured to direct the first and second light pulses toward a front surface of a microelectronic substrate in a manner that creates a first return light pulse corresponding to a reflectance of the first light pulse and a second return light pulse corresponding to a reflectance of the second light pulse;  
       a sensor configured to receive the first return light pulse and the second return light pulse, the sensor being capable of generating a first measured intensity of the first return light pulse and a second measured intensity of the second return light pulse; and  
       a computer coupled to the sensor, the computer having a database and a computer readable medium, the database containing a plurality of sets of reference reflectances in which each set has a first reference component defined by a reflectance intensity of the first light pulse and a second reference component defined by a reflectance intensity of the second light pulse from a selected surface level in a layer of material on the microelectronic substrate, and the computer readable medium containing a computer readable program that causes the computer to control a parameter of the planarizing machine when the first and second measured intensities correspond to the first and second reference components of a selected reference reflectance set.  
     
     
       20. The planarizing machine of  claim 19  wherein: 
       the database includes an endpoint reference reflectance set having a first reference component corresponding to a first endpoint intensity of the first return light pulse from an endpoint surface and a second reference component corresponding to a second endpoint intensity of the second return light pulse from the endpoint surface; and  
       the computer readable program causes the computer to terminate a planarizing cycle when the first and second measured intensities correspond to the first and second endpoint intensities, respectively.  
     
     
       21. The planarizing machine of  claim 19  wherein: 
       the first emitter comprises a red LED that generates a red first light pulse having a wavelength of approximately 600 nm to 780 nm; and  
       the second emitter comprises a green LED that generates a green second light pulse having a wavelength of approximately 490 nm to 577 nm.  
     
     
       22. The planarizing machine of  claim 19  wherein the sensor includes a single photo detector that measures both the first intensity of the first return light pulse and the second intensity of the second return light pulse. 
     
     
       23. The planarizing machine of  claim 19  wherein the light source further comprises a third emitter that generates a third light pulse having a third color different than the first and second colors. 
     
     
       24. The planarizing machine of  claim 23  wherein: 
       the first emitter comprises a red LED that generates a red first light pulse having a wavelength of approximately 600 nm to 780 nm and a red first return light pulse;  
       the second emitter comprises a green LED that generates a green second light pulse having a wavelength of approximately 490 nm to 577 nm and a green second return light pulse; and  
       the third emitter comprises a blue LED that generates a blue third light pulse having a wavelength of approximately 450 nm to 490 nm and a blue third return light pulse.  
     
     
       25. The planarizing machine of  claim 24  wherein the sensor comprises a single photo detector that measures the first intensity of the red first return light pulse, the second intensity of the green second return light pulse, and a third intensity of the blue third return light pulse. 
     
     
       26. The planarizing machine of  claim 24  wherein: 
       the database includes an endpoint reference reflectance set having a first reference component corresponding to a first endpoint intensity of the red first return light pulse from an endpoint surface, a second endpoint component corresponding to a second intensity of the green second return light pulse from the endpoint surface, and a third reference component corresponding to a third endpoint intensity of the blue third return light pulse from the endpoint surface; and  
       the computer readable program causes the computer to terminate a planarizing cycle when the first, second and third measured intensities correspond to the first, second and third endpoint intensities, respectively.  
     
     
       27. The planarizing machine of  claim 24  wherein: 
       the database includes a reference reflectance set corresponding to an interface between two layers of material on a substrate, wherein the reference set has a first reference component corresponding to a first interface intensity of the red first return light pulse from an interface surface, a second reference component corresponding to a second interface intensity of the green second return light pulse from the interface surface, and a third reference component corresponding to a third interface intensity of the blue third return light pulse from the interface surface; and  
       the computer readable program causes the computer to indicate when the first, second and third measured intensities correspond to the first, second and third interface intensities, respectively.  
     
     
       28. A planarizing machine for mechanical and/or chemical-mechanical planarization of a microelectronic substrate, comprising: 
       a table having a support surface;  
       a planarizing pad on the support surface of the table, the planarizing pad having an optically transmissive window;  
       a substrate carrier assembly having a drive system and a carrier head coupled to the drive system, the carrier head being configured to hold a substrate and the drive system being capable of moving the carrier head to engage the substrate with the planarizing pad, wherein the carrier head and/or the table is movable relative to the other to rub the substrate against the planarizing pad;  
       a light system having a light source and a light sensor, the light source having a first emitter that emits a first light pulse having a first color and a second emitter that emits a second light pulse having a second color different than the first color, the light source being configured to direct the first and second light pulses through the window in the planarizing pad and against a front surface of a microelectronic substrate in a matter that creates a first return light pulse from the first light pulse and a second return light pulse from the second light pulse, the light sensor having a single photo detector configured to receive the first return light pulse and the second return light pulse, and the photo detector being capable of measuring both a first intensity of the first return light pulse and a second intensity of the second return light pulse; and  
       a controller coupled to the sensor, the controller controlling a parameter of planarizing the microelectronic substrate according to the first and second intensities of the first and second return light pulses measured by the photocell.  
     
     
       29. The planarizing machine of  claim 28  wherein the controller comprises a computer having: 
       a database containing an endpoint reference reflectance set having a first reference component corresponding to a first endpoint intensity of a reflectance of the first light pulse from an endpoint surface and a second reference component corresponding to a second endpoint intensity of the second light pulse from the endpoint surface; and  
       a computer readable program that causes the computer to terminate a planarizing cycle when the first and second measured intensities correspond to the first and second endpoint intensities, respectively.  
     
     
       30. The planarizing machine of  claim 28  wherein: 
       the first emitter comprises a red LED that generates a red first light pulse having a wavelength of approximately 600 nm to 780 nm; and  
       the second emitter comprises a green LED that generates a green second light pulse having a wavelength of approximately 490 nm to 577 nm.  
     
     
       31. The planarizing machine of  claim 28  wherein the light source further comprises a third emitter that generates a third light pulse having a third color different than the first and second colors. 
     
     
       32. The planarizing machine of  claim 31  wherein: 
       the first emitter comprises a red LED that generates a red first light pulse having a wavelength of approximately 600 nm to 780 nm and a red first return light pulse;  
       the second emitter comprises a green LED that generates a green second light pulse having a wavelength of approximately 490 nm to 577 nm and a green second return light pulse; and  
       the third emitter comprises a blue LED that generates a blue third light pulse having a wavelength of approximately 450 nm to 490 nm and a blue third return light pulse.  
     
     
       33. The planarizing machine of  claim 32  wherein the single photo detector measures the first red intensity of the first return light pulse, the second green intensity of the second return light pulse, and a third intensity of the blue third return light pulse. 
     
     
       34. The planarizing machine of  claim 32  wherein the controller comprises a computer having: 
       a database including an endpoint reference reflectance set having a first reference component corresponding to a first endpoint intensity of a reflectance of the red first light pulse from an endpoint surface, a second reference component corresponding to a second endpoint intensity of the green second light pulse from the endpoint surface, and a third reference component corresponding to a third endpoint intensity of a reflectance of the blue third light pulse from the endpoint surface; and  
       a computer readable program that causes the computer to terminate a planarizing cycle when the first, second and third measured intensities correspond to the first, second and third endpoint intensities, respectively.  
     
     
       35. The planarizing machine of  claim 32  wherein the controller comprises a computer having: 
       a database containing a reference reflectance set corresponding to an interface between two layers of material on a substrate, wherein the reference set has a first reference component corresponding to a first interface intensity of a reflectance of the red first light pulse from an interface surface, a second reference component corresponding to a second interface intensity of the green second light pulse from the interface surface, and a third reference component corresponding to a third interface intensity of a reflectance of the blue third light pulse from the interface surface; and  
       a computer readable program that causes the computer to indicate when the first, second and third measured intensities correspond to the first, second and third interface intensities, respectively.  
     
     
       36. A method of planarizing a microelectronic device substrate, comprising: 
       contacting a face of the microelectronic device substrate with a planarizing surface of a planarizing pad;  
       moving the substrate and/or the planarizing pad to rub the planarizing surface against the face of the substrate;  
       directing a first light pulse toward the face of the substrate, the first light pulse having a first color;  
       measuring a first intensity of a first return light pulse reflecting from the substrate, the first return light pulse having the first color;  
       directing a second light pulse toward the face of the substrate, the second light pulse having a second color different than the first color;  
       measuring a second intensity of a second return light pulse reflecting from the substrate, the second return light pulse having the second color;  
       comparing the first and second measured intensities with first and second reference components of sets of reference reflectances; and  
       controlling a parameter of the planarizing cycle of the substrate when the first and second measured intensities at least approximately correspond to the first and second reference components of a selected set of reference reflectances.  
     
     
       37. The method of  claim 36  wherein: 
       directing a first light pulse comprises emitting a red light pulse having a wavelength of approximately 600 nm to 780 nm; and  
       directing a second light pulse comprises emitting a green light pulse having a wavelength of approximately 490 nm to 577 nm.  
     
     
       38. The method of  claim 36 , further comprising: 
       directing a third light pulse toward the face of the substrate, the third light pulse having a third color;  
       measuring a third intensity of a third return light pulse reflecting from the substrate, the third return light pulse having the third color; and  
       comparing the third measured intensity with a third component of the sets of reference reflectances.  
     
     
       39. The method of  claim 38  wherein controlling the parameter of the planarizing cycle comprises changing the parameter when the first, second and third measured intensities correspond to the first, second and third reference components of a selected set of reference reflectances. 
     
     
       40. The method of  claim 36  wherein controlling the parameter of the planarizing cycle comprises terminating the planarizing cycle when the first and second measured intensities correspond to the first and second reference components of an endpoint set of reference reflectances. 
     
     
       41. A method of planarizing a microelectronic device substrate, comprising: 
       contacting a face of the substrate with a planarizing surface of a planarizing pad;  
       moving the substrate and/or the planarizing pad to rub the planarizing surface against the face of the substrate;  
       impinging a first light pulse against the face of the substrate at a first time interval, the first light pulse having a first color;  
       directing a second light pulse against the face of the substrate at a second time interval, the second light pulse having a second color;  
       sensing a first intensity of a first return light pulse corresponding to the first light pulse reflecting from the substrate and a second intensity of a second return light pulse corresponding to the second light pulse reflecting from the substrate; and  
       controlling a parameter of the planarizing cycle of the substrate according to the first and second intensities of the first and second return light pulses, wherein controlling the parameter of the planarizing cycle comprises terminating the planarizing cycle when the first and second measured intensities correspond to a first and a second reference component of an endpoint set of reference reflectances respectively.  
     
     
       42. The method of  claim 41  wherein: 
       impinging a first light pulse comprises emitting a red light pulse having a wavelength of approximately 600 nm to 780 nm; and  
       directing a second light pulse comprises emitting a green light pulse having a wavelength of approximately 490 nm to 577 nm.  
     
     
       43. The method of  claim 41 , further comprising: 
       directing a third light pulse toward the face of the substrate, the third light pulse having a third color;  
       measuring a third intensity of a third return light pulse reflecting from the substrate, the third return light pulse having the third color; and  
       controlling a parameter of the planarizing cycle comprises changing the parameter according to the first, second and third measured intensities.